1. Field of the Invention
This invention relates generally to the field of perpendicular magnetic recording (or write) heads having a P3 magnetic layer and more particularly, to an improved method of fabricating the P3 magnetic layer resulting in small track width.
2. Description of the Prior Art
As the recording density of magnetic hard drives (or disc drives) increases, a physical limitation is experienced using longitudinal recording systems partly due to thermal relaxation known as super-paramagnetism. That is, the density requirements for meeting today's storage needs are simply not attainable with longitudinal recording systems. To provide further insight into this problem, it is anticipated that longitudinal recording systems will lose popularity as storage capacities in excess of about 150 Gigabytes-per-square-inches become a requirement. These and other factors have lead to the development and expected launch of perpendicular recording heads or write heads. Perpendicular recording is promising in pushing the recording density beyond the limit of longitudinal recording.
Accordingly, perpendicular recording potentially can support much higher linear density than longitudinal recording due to lower demagnetizing fields in recorded bits, which diminish when linear density increases.
A magnetic recording head for perpendicular writing generally includes two portions, a write head portion or head for writing or programming magnetically-encoded information on a magnetic media or disc and a reader portion for reading or retrieving the stored information from the media.
The write head or recording head of the magnetic head or disc drive for perpendicular recording typically includes a main pole and a return pole which are magnetically separated from each other at an air bearing surface (ABS) of the writer by a nonmagnetic gap layer, and which are magnetically connected to each other at a region distal from the ABS at a back gap closure (yoke). This structure is a single-pole write head because while a main pole and return pole are referred thereto, the return pole is not physically a pole, rather, it serves to close the loop with the main pole and the soft under layer for magnetic flux circuit.
Positioned at least partially between the main and return poles are one or more layers of conductive coils encapsulated by insulation layers. The ABS is the surface of the magnetic head immediately adjacent to the perpendicular medium.
To write data to the magnetic medium, an electrical current is caused to flow through the conductive coil, thereby inducing a magnetic field across the gap between the main and return poles. By reversing the polarity of the current through the coil, the polarity of the data written to the magnetic media is also reversed.
The goal with perpendicular write heads is to reduce the size of various components or structures thereof, such as what is commonly known as the P3 region or layer. By doing so, undesirable erasure of adjacent tracks during write operations is reduced or eliminated. Currently, photoresist techniques, such as the well known method of Dumedi is used for forming P3 layers but causing undesirable changes to dimensions during the process therefore causing difficulty in controlling the track width. Thus, a narrow P3 layer construction is nearly impossible with known techniques. Also, plating thickness is limited with the Dumedi technique. Moreover, consistent track widths are unattainable, particularly, across wafers.
Therefore, the need arises for a write head employed in perpendicular recorders or disc drives having a P3 layer that is formed in a way so as to reduce its size and therefore smaller track width and avoid or minimize undesirable erasure of adjacent tracks during write operations.